Turnbull government cabinet minister Darren Chester completed the purchase of an investment property on a taxpayer-funded trip to Melbourne in which he also attended the Australian Open tennis and a soccer match.

Stood aside Health Minister Sussan Ley's frequent taxpayer-funded trips to the Gold Coast, where she bought an $800,000 investment property, have reignited debate about whether politicians' entitlements are too generous and whether the lines between personal and private business are too blurred.

According to Mr Chester's register of interests, he purchased a two-bedroom unit in Ivanhoe, a leafy suburb in north-east Melbourne, while on official business on January 27 2016. A spokeswoman said this was the date of settlement for the property and that Mr Chester collected the keys to the unit on this date.

At the time Mr Chester, now the Minister for Transport and Infrastructure, was the assistant minister for defence.

A spokeswoman said Mr Chester's official business included representing the government at an Australian Defence Force enlistment ceremony at the Shrine of Remembrance on January 27.

After attending several Australia Day events in his electorate of Gippsland, Mr Chester attended a football match that night between the Melbourne Victory and Sydney FC at the invitation of Victory chairman Tony Di Pietro. The following night he attended the Australian Open quarter finals as a guest of Qantas.

Mr Chester's spokeswoman said the visits to the football and tennis were part of Mr Chester's official business over the Australia Day period.

"The Minister declared the events on the register of interests, and is confident that his travel was in accordance with the rules," the spokeswoman said.

"The Minister did not claim accommodation in late November when in Melbourne to purchase the unit."

Mr Chester bought the apartment on November 28, the spokeswoman said.

Mr Chester's cabinet colleague Sussan Ley stood down from the ministry on Monday following revelations she bought a luxury apartment while on a taxpayer-funded trip to the Gold Coast.

Ms Ley, who said the purchase was "neither planned nor anticipated", has agreed to repay her claims for the trip as well as other trips to the Gold Coast.

"I realised that my purchase of the unit changed the character of the occasion to one of a more personal nature and I should have adjusted my claim accordingly," she told reporters on Monday.

It has also been revealed that three government ministers - Attorney-General George Brandis, Immigration Minister Peter Dutton and Communications Minister Mitch Fifield - billed the taxpayer to travel to a New Year's Eve party hosted by Prime Minister Malcolm Turnbull. The other ministers who attended the event did not charge taxpayers.

"A clear definition of what official business is is obviously at the centre of the changes that need to be made - and will be made - by the government in order to give the Australian people confidence that their hard-earned taxpayer dollars are respected and they can have confidence in the system," she said.

Matthew Knott is a Fairfax Media reporter based in the United States. He previously worked in the Canberra press gallery and recently finished a Masters of Journalism at Columbia University in New York.